I'm gonna have to agree with a few other sentiments on how Wisp's current kit seem somewhat jumbled. Given her appearance, I was actually expecting something different. Her one is just way too immobile for a game emphasizing large amounts of movement, and her three being tied to it, albeit quite appealing to look at, only roots her into place just that much more. Wisp's four (again, cool looking), just doesn't mesh with her theme all that well either. The only ability that I find to fit well on her currently is her two.
A couple suggestions -
Make it so that her one, rather than rooting the reservoirs down, makes them orbiting objects that provide the buffs to anybody within range, lasting for a duration once they get further away. With this change to her one, it would automatically make her three much more useful right off. Big bonus to @Aenris for the idea of making them look like Will-o-wisps.
Rather than a big ol' sun of burning-burniness, I'd say it should create a massive aura of enchanted mist surrounding Wisp, providing a small amount of damage to enemies in range that also gives them debuffs such as a chance to inflict blindness, heightened damage vulnerability, and maybe a rare chance of radiation-induced friendly-fire.